Skip to contentSkip to conversation

sctp: implement SIOCINQ ioctl() (take 2)

PATCH New Diego Elio 'Flameeyes' Pettenò 1 participant 1 message Jun 24, 2010

Subsystems (2)
Networking SCTP protocol
lore
Share & tools
lore

Diego Elio 'Flameeyes' Pettenò

author
#0 lore raw

PATCH 1/1 sctp: implement SIOCINQ ioctl() (take 2)

This simple patch copies the current approach for SIOCINQ ioctl() from DCCP into SCTP so that the userland code working with SCTP can use a similar interface across different protocols to know how much space to allocate for a buffer.

---
 net/sctp/socket.c |   35 ++++++++++++++++++++++++++++++++++-
 1 files changed, 34 insertions(+), 1 deletions(-)
net/sctp/socket.c +34 -1
index 44a1ab0..f339383 100644
@@ -3595,7 +3595,40 @@ out:
 /* The SCTP ioctl handler. */
 SCTP_STATIC int sctp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 {
-	return -ENOIOCTLCMD;
+	int rc = -ENOTCONN;
+
+	sctp_lock_sock(sk);
+
+	/*
+	 * SEQPACKET-style sockets in LISTENING state are valid, for
+	 * SCTP, so only discard TCP-style sockets in LISTENING state.
+	 */
+	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
+		goto out;
+
+	switch (cmd) {
+	case SIOCINQ: {
+		struct sk_buff *skb;
+		unsigned long amount = 0;
+
+		skb = skb_peek(&sk->sk_receive_queue);
+		if (skb != NULL) {
+			/*
+			 * We will only return the amount of this packet since
+			 * that is all that will be read.
+			 */
+			amount = skb->len;
+		}
+		rc = put_user(amount, (int __user *)arg);
+	}
+		break;
+	default:
+		rc = -ENOIOCTLCMD;
+		break;
+	}
+out:
+	sctp_release_sock(sk);
+	return rc;
 }
 
 /* This is the function which gets called during socket creation to
Signature · 1 line
1.7.1